This invention relates to a bore measurement apparatus and method and, more particularly, to a bore measurement apparatus and method for measuring with a single measurement apparatus the inner diameter of a bore and the height of a cutting tool mounted on a boring bar, without adjusting the apparatus.
The inner diameter of a bore typically is measured with calipers which are placed within the bore and then extended outwardly to measure the bore's inner diameter. To place the calipers within the bore, a boring bar for mounting a cutting tool thereon should be removed from the bore. After measuring the inner diameter, the boring bar must be remounted within the bore and the cutting tool adjusted thereon prior to beginning the next cutting iteration. Removal of the boring bar is also generally required for measurement of the inner diameter with a micrometer. Repeated removal and remounting of the boring bar in the bore for each iteration of the cutting process is time consuming and may lead to mispositioning of the apparatus and inaccurate cutting of the bore's inner surface. Moreover, the use of calipers or a micrometer to measure the inner diameter of a bore may lead to inaccurate measurements because an operator must visually read the diameter from the device.
The height of a cutting tool mounted on a boring bar typically is measured with calipers by placing one caliper arm on the upper edge of the cutting tool and one arm on the bottom of the boring bar directly opposite from the cutting tool. The operator then subtracts the diameter of the boring bar from the measurement to determine the cutting tool height. The use of calipers to measure the height of a cutting tool, or the diameter of a bore that would be cut by the cutting tool, may lead to inaccurate measurements because the operator must visually read the measurement from the device. This disadvantage is also present when measuring the outer diameter of the cutting tool with a micrometer. In addition, the elongate caliper arms or the micrometer measurement screw, in certain situations, may not fit within the bore to measure the inner diameter or may not fit around the boring bar and the cutting tool to measure the outer diameter.